Educational device



Feb. 10, 1942. R. B. JoHNsoN EDUCATIONAL DEVICE 18 Sheets-Sheet 1 Original Filed June 21, 1938 VENTOR Q ATTORNEY' Feb. l0, 1942. R. B. JOHNSON i EDUCATIONAL DEVICE original Filed June 21, 1938 18 ShetS-Shee't 2 INVZTOR ATTORNEY 2f j. .12..92 a

NM nw VINE- JM@ a n Feb. l0, 1942. R. B. JOHNSON EDUCATIONAL DEVVICE Original Filed June 2l, 1938 18 Sheets-Sheet 3 ATTORNEY Feb. 10, 1942. R. B. JOHNSON EDUCATIONAL DEVICE 18 Sheets-Sheet 4A l Original Filed June 21, 1938 INVENToR Q @lm ATTORNEY Feb. 1o, 1942.

Original Filed June 21, 1938 R. B. JOHNSON EDUCATIONAL DEVICE 18 Sheets-Sheet 5 /Izsosct Mg inner msm-imm DAILY TIfrS BELIEFS ms sccrmu s wf scans la C o INVENTOR AT'ToRNEY Feb. l0, 1942.

R. B. JOHNSON l.

EDUCATIONAL DEVICE 18 Sheets-Sheet 7 original Filedqune 21, 1938 ATTNEY Feb. l0, 1942. R. B. JoHNsoN v 2,272,411

EDUCATIONAL DEVICE original Filed June 21, 1938 18 sheets-sheet 8 77 7a 7s 1s 5 80 /P/awr a 05 j 5K K iNvl-:NTOR y |96 W fw' A Feb. 10, 1942. R B JOHNSON 2,272,411

EDUCATIONAL DEVICE Original Filed June 21, 1938 18 Sheets-Sheet 9 m G W INVEIF'I'OR 7% ATT'ORNEY FIC-lll 18 Sheets-Sheet 10 :i @l I ro a 1 OOOOO `FIG R. B. JoHNsoN EDUCATIONAL DEVICE original Filed June 21. 19:58

Feb. 1o, 1942.y

Feb. 10, 1942. R B JOHNSQN 2,272,411

n A a n 8 INVENTO ATT'ORNEY FI J6.

Feb. l0, 1942.

R. B. JOHNSON EDUCATIONAL DEVICE Original Filed June 21, 1938 FIG. I7.

1a sheetssheet 12 136 '42 48 11a 140 f4@ y 42 i04- 143 H8 105 |03 ,69 143 121 107 ,2 34 75 173 f 163 193 11e ,1'11I |11 1"' 11"... 37 9 120 .1 11| l l l l i 0 114 122 Feb. 10, 1942. R. B. JoHNsoN EDUCATIONAL DEVICE 18 Shee'ts-Shee'rl 14 Original Filed June 21, 1938 /q my 282 283( 3/4 \289 229 237 y lNVTOR ATTORNEY Feb. 10, 1942. R. B. JOHNSON 2,272,411

EDUCATIONAL DEVICE Original Filed June 2l, 1938 18 Sheets-Sheet 15 Flame. Flazlb.

I 'INVITOR i Feb. 10, 1942. R. B. JOHNSON 2,272,411

I EDUCATIONAL DEVICE Original Filed June 21. 1958 1.8 Sheets-Sheet 16 FIG.23.

12e-ai v m 175 l 5'2/4 INVENTOR- i -98 f MMM TWG/T U vvvv ATTORNEY Feb. 1o, 1942. R, B; JOHNSON 2,272,411

EDUCATIONAL DEVICE Original Filed June 2l, 1938 18 Sheets-Sheet 17 ATTORNEY Feb. l0, 1942. R. B. JOHNSON 2,272,411

EDUCATIONAL DEVICE Original Filed June 21, 1938 18 Sheets-Sheet 18 ATTORNEY Patented Feb. 10, 1942 EDUCATIONAL DEVICE Beynold B. Johnson, Binghamton, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Original application June 21, 1938, Serial No.

Divided and this application November 7, 1940, Serial N0. 364,654

(Cl. 235f61.6)

6 Claims.

This is a division of application Serial No. 214,922, filed June 21, 1938, which relates to a machine for electrically grading response sheets upon which an examinee has designated responses by means of pencil marks. The machine constitutes improvements over the machine shown in my Patent No. 2,113,620, granted April 12, 1938.

The main object of the invention is to extend the usefulness of a machine operating according to the principles of my former arrangement, especially in the handling of objective tests of the multiple-choice or true-false type, the responses to which may be recorded by making a record in one of several positions on a response sheet. 'I'he machine is designed to handle response sheets having a maximum capacity on each side of 150 ve-choice, 300 two-choice or 750 single-choice questions. In other words, the response sheet has 750 possible marking positions to be identified or numbered to correspond to questions given orallyor contained in a separate question sheet or booklet or may be printed on the answer sheet. Once the examinee decides which choice is the correct answer for a particular question, he merely makes a heavy short line on the response sheet in the number space corresponding to the number of his chosen answer,

The functioning-of the machine depends on the fact that a soft lead pencil or special ink mark is electrically conductive and that the amount of' current owing through each pencil or ink mark may be controlled and kept to a uniform unit, whether the mark is very heavy or relatively light.

3 When the response sheet is inserted in the machine it is pressed against a contact plate lcontaining 750 sets of sensing blades corresponding to the 750 response positions on the response sheet. These sets of sensing blades consist each of :live small parallel metal blades which are connected alternately to the positive and negative sides of the circuit. Whenever a pencil mark is pressed against one of the sets of sensing blades, it closes the electric gap between the positive and negative blades and a unit of current ilows through the circuit. Ii pencil marks are pressed against ten oi the sets of contact blades, ten units of current flow through the circuit. It a pencil mark is suiliciently long, it will bridge the electric gap four times; if the pencil mark is very short, it will bridge the gap only once, but in either case the unit of current ilowing through the circuit from the pencil-mark-bridge remains practically constant. This result is achieved by connecting in series with each contact unit a high resistance current' limiting resistor which permits only a unit amount of current to llow into a meter circuit from each pencil mark.

The machine distinguishes between right and wrong answers by means of a perforated key sheet which automatically divides the sensing blade units into two groups, the rights and the wrongs From this division, two meter circuits result, one carrying the aggregate of the units of current from the correct responses and the other carrying the aggregate of the units of current from the incorrect responses.

The machine may be variously set, by means of various switching devices, to score in terms of the number right by routing the current from the`rights circuit through a large milliameter. This meter is ordinarily calibrated directly in terms of the unit of current flowing through the meter from each small circuit and hence the reading on the meter is equal to the number of right responses on the answer sheet being pressed against the sensing blades. The score indicated on the meter is recorded by the operator on the exposed margin of the response sheet or on a separate record sheet or the operator may call the score to a recording clerk.

If the score is in terms of the number wrong. the current from the wrongs circuit is routed through the meter which indicates to the operator the number wrong.

If the score is in terms of rights minus wrongs, the wrongs" circuit is connected to the opposite side of the meter from the rights 5 circuit, so that the meter reading is the diiIerence between the two currents, thus registering= the rights minus the wrongs The machine may be adjusted to obtain the score in terns oi the rights minus one-halt 'the wrongs, in which case one-half the current from the wrongs ordinarily iiowing through the motor is shunted past the meter and thus the score registered is the rights minus one-half the wrongs.

Similarly, the score can be obtained in terms of the rights minus any fraction of the wrongs.

The machine may be adjusted so that each response may carry a value of more than 1. In doing this the applied voltage is increased, so that the current flowing through any response circuit may be greater than flows ordinarily.

if a test of 77 items, for example, is scored in terms of percentage, the voltage is stepped up so that a score of 77 is indicated on the meter as a score of 100. This is equivalent to multiplying each score by 1.298. With such setting, the resection of the holder.

sponse sheets are scored directly in terms of the percentage of rights, the percentage of wrongs or the percentage of rights minus the percentage of or some fraction of the wrongs. If the machine is adjusted so that the score is in terms of rightsV minus twice the wrongs, the voltage is doubled for all responses, but one-.half olf the current from the right responses ordinarily iiowing through the meter is shunted past the meter. Hence, the current resulting from each right response moves the meter needle up one point and scream the current resulting from each wrong response n moves the meter down two points.

The machine has three sets of controls which makes it possible to score with one insertion of the response sheet three different tests or three diierent parts of one test, and each test can be scored by any formula in terms of rights and wrongs. The machine is further provided with a negative score key which reverses the meter connections so that current which ordinarily causes the meter to deect below will cause it to deect above 0. This key is utilized in such cases Where the machine is set to score a number of rights minus wrongs and the number of l wrongs is greater.

The principal object of the present invention is to provide an arrangement in the form of a removable unit called an item-weighting unit which contains selectively lsettable switches through which each individual response position may be given a different Weight. This unit directs the current flowing from the individual sensing pins in variable proportions so that the current passing through the meter from any given mark will be any desired one of ten possible fractions of a value.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by Way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a front view of the machine with the casing partially broken away to show the interior construction.

Fig. 2 is a plan view of the` machine with the score indicator and part of the casing removed.

Fig. 2a is a detail of the operating key connections.

Fig. 3 is an enlarged section taken substantially along lines 3-3 of Fig. 2.

Fig. 4 is a view similar to Fig. 3 with the parts in moved or response sheet sensing position.

Fig. 5 is a specimen of a response sheet marked in accordance with an examinees selections.

Fig. 6 is a specimen of a record marked to represent a plurality of different measures whose average is to be obtained by the machine.

Fig. 7 is a specimen of the main key sheet perforated in positions representing the correct answers.

Fig. 8 is a similar specimen of the secondary key sheet.

Fig. 9 is an isometric View showing the key sheet holder inserted in the machine.

Fig. 10 is a view at an enlarged scale showing the key sheet holder and the manner in which the key sheets control the positioning of various pins. 'Ihe section is taken substantially along the lines Iii-H) of Fig. 9.

Fig. 10a is a similar view taken at another taken substantially along 10a-l0@ o Fig. 9.

In Fig. 10a. the section is Fig; l1 is a detail view of the response sheet sensing unit.

Fig. 12 is a plan view of the unit broken away to show lthe interior construction.

Fig. 13 is a detail of the resistor panel.

Fig. 14 is an enlarged detail of Fig. 13 taken substantially along the 'lines itl of Fig. 13.

Fig. 15 is an enlarged detail of one of the sensing devices shown in Fig. l2.

Fig. 15a is a detail showing a modified arrangement enabling the sensing blades to read marks made in the forrn of perforations.

Fig. 16 is a detail View showing the key sheet pin unit and the manner in which it is supported in the machine.

Fig. 1'7 is a sectional view taken substantially along lines l--I'i of Fig. 3.

Fig. 18 is an isometric view showing the unit weighting mechanism inserted in the reciprocable carriage.

Fig. 19 is a plan section of the unit takenV substantially along lines ISF-I9 yof Fig. 18.

Fig. 20 is a. vertical section through the same mechanism.

Fig. 21 is a fragment of a record having columns ci perforations representing certain data.

Figs. 21a and 2lb arey fragments of records Whose data is represented by vertical pencil or ink lines, whichy data is to be compared with the data on the record of Fig. 21. Y

Fig. 22 is a view showing the control circuit for the driving motor.

Figs. 23, 23a and 23h, placed side by side in the order named, constitute a wiring diagram of the electric circuits of the machine.

Response sheet va pencil or pen co-extensive with the parallel lines. Thus, for example, if the first question on an examination required the selection of one -of five possible answers, and if the examinee selected the first given answer as his choice, a pencil rnark would be made in the 1 position opposite question 1.` VIn the example shown in Fig. 5. the first thirty-eight response positions constitute one' test designated Test A. The response positions-39 to 75 constitute a second test designated Test B, and the response positions 76 to constitute a third. designated Test C.

In operating the machine, all the responses may be scored as a single test or each of. the three tests may be scored separately or any two of them may oe taken together to obtain their combined score. The arrangement shown in Fig. 5 provides for thirtyl responses in each of the ve columnsor positions in al1 and as many or as few of these positions may be utilized in accordance with the requirements of the test or tests given.

Main key sheetL The main key sheet K is shown in Fig. "I and is providedy with columnsV and rows of indicating positions Ki corresponding to the indicating positions Ri on the response sheet. Preparation of' this sheet is eiected by perforating the posi- 

